package com.bookkeeping.bookkeepingapi.service.util;

import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

public class MD5Util {

    private static final char[] DIGITS = {'0', '1', '2', '3', '4', '5', '6',
            '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'};



    public static MessageDigest getMd5Digest() {
        try {
            return MessageDigest.getInstance("MD5");
        } catch (NoSuchAlgorithmException e) {
            throw new RuntimeException(e.getMessage());
        }
    }

    //字符串进行md5加密后，再转化成大写  32位大写MD5值
    public final static String MD5(String s) {
        try {
            byte[] btInput = s.getBytes();
            // 获得MD5摘要算法的 MessageDigest 对象
            MessageDigest mdInst = getMd5Digest();
            // 使用指定的字节更新摘要
            mdInst.update(btInput);
            // 获得密文
            byte[] md = mdInst.digest();
            // 把密文转换成十六进制的字符串形式
            int j = md.length;
            char str[] = new char[j * 2];
            int k = 0;
            for (int i = 0; i < j; i++) {
                byte byte0 = md[i];
                str[k++] = DIGITS[byte0 >>> 4 & 0xf];
                str[k++] = DIGITS[byte0 & 0xf];
            }
            return new String(str).toUpperCase();
        } catch (Exception e) {
            e.printStackTrace();
            return null;
        }
    }

    public static void main(String[] args) {
        System.out.println(MD5("appSecretusernamevalue1appKeyvalue2codevalue3appSecret"));
    }
}
